For the early 3D display technology, a 3D spectacle is mainly used to view a 3D image, while a binocular parallax-based autostereoscopic 3D display device is used as a mainstream product now. Grating is one of the elements capable of achieving the autostereoscopic 3D displaying, as shown in FIG. 1, which is a schematic view illustrating the principle of separating light transmission paths for a left-eye image and a right-eye image by the grating. Due to the existence of the grating 1, the left-eye image displayed by a display panel 2 can merely be viewed by a left eye, and the right-eye image can merely be viewed by a right eye, so as to provide a stereoscopic parallax effect for a viewer, thereby achieving the 3D display.
FIG. 2 is a schematic view illustrating light transmission paths when human eyes move while viewing a 3D image. As shown in FIG. 2, with respect to the conventional 3D displaying, when the left-eye 100 of an observer is at position A and observes an image, a left-eye image on the display panel 2 (i.e., the dark parts on the display panel 2 in FIG. 1) can just be obtained. However, when the left-eye 100 of the observer moves to position B and observes the image, an image produced for the left-eye 100 after going through the grating further includes a right-eye image part (i.e., the white parts on the display panel 2 in FIG. 1), which results in crosstalk.
Therefore, with respect to the conventional grating-type autostereoscopic 3D displaying, observing positions are relatively fixed, i.e., the observing positions cannot move away from several points within an optimal observing plane. When the observing positions do move away therefrom, crosstalk increases significantly, which results in adverse effects on the observing needs.